PXS20RM Datasheet, PDF (468/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Enhanced Motor Control Timer (eTimer)
PHASEA
PHASEB
COUNT
+1 +1 +1 +1 +1 +1 +1 [phone]
UP/DN
Figure 20-24. Quadrature Incremental Position Encoder
20.5.2.6 SIGNED-COUNT Mode
If the CNTMODE field is set to ‘101’, the counter counts the primary clock source while the selected
secondary source provides the selected count direction (up/down).
20.5.2.7 TRIGGERED-COUNT Mode
If the CNTMODE field is set to ‘110’, the counter will begin counting the primary clock source after a
positive transition (negative if SIPS = 1) of the secondary input occurs. The counting will continue until
a compare event occurs or another positive input transition is detected. Subsequent secondary positive
input transitions will continue to restart and stop the counting until a compare event occurs.
Primary
Secondary
CNTR
12
13
14
15
16
17
18
OFLAG
COMP1 = 18
Figure 20-25. Triggered Count Mode (Length=1)
20.5.2.8 ONE-SHOT Mode
If the CNTMODE field is set to ‘110’, and the counter is set to reinitialize at a compare event (LENGTH
=1), and the OFLAG OUTMODE is set to ‘0101’ (cleared on init, set on compare), the counter works in
a “One-Shot Mode”. An external events causes the counter to count, when terminal count is reached, the
output is asserted. This “delayed” output can be used to provide timing delays.
Primary
Secondary
CNTR
0
1
2
3
4
0
1
OFLAG
LOAD = 0, COMP1 = 4
Figure 20-26. One-Shot Mode (Length=1)
20-26
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor